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Title: Evolution of a minimal cell
Abstract Possessing only essential genes, a minimal cell can reveal mechanisms and processes that are critical for the persistence and stability of life1,2. Here we report on how an engineered minimal cell3,4contends with the forces of evolution compared with theMycoplasma mycoidesnon-minimal cell from which it was synthetically derived. Mutation rates were the highest among all reported bacteria, but were not affected by genome minimization. Genome streamlining was costly, leading to a decrease in fitness of greater than 50%, but this deficit was regained during 2,000 generations of evolution. Despite selection acting on distinct genetic targets, increases in the maximum growth rate of the synthetic cells were comparable. Moreover, when performance was assessed by relative fitness, the minimal cell evolved 39% faster than the non-minimal cell. The only apparent constraint involved the evolution of cell size. The size of the non-minimal cell increased by 80%, whereas the minimal cell remained the same. This pattern reflected epistatic effects of mutations inftsZ, which encodes a tubulin-homologue protein that regulates cell division and morphology5,6. Our findings demonstrate that natural selection can rapidly increase the fitness of one of the simplest autonomously growing organisms. Understanding how species with small genomes overcome evolutionary challenges provides critical insights into the persistence of host-associated endosymbionts, the stability of streamlined chassis for biotechnology and the targeted refinement of synthetically engineered cells2,7–9.  more » « less
Award ID(s):
1840301 1818344 1840320 2221237
PAR ID:
10481403
Author(s) / Creator(s):
; ; ; ; ; ; ; ;
Publisher / Repository:
Nature
Date Published:
Journal Name:
Nature
Volume:
620
Issue:
7972
ISSN:
0028-0836
Page Range / eLocation ID:
122 to 127
Subject(s) / Keyword(s):
Experimental evolution, Bacterial genes, Genome evolution, Synthetic organisms, Molecular evolution
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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